Yes I completely understand. I was just making the point that it is entirely possible that what is there now is indeed totally noncombustible if you are able to determine the studs installed in 2003 are metal. If it was built and inspected in 2003 and passed the final inspection for your certificate of occupancy, it was therefore, determined to be up to code and thereby safe.
So your choices as I see them are as follows:
A. If you can determine that it was inspected, then I would (were it my home) accept that
as fact that it is safe and be fine with leaving it as it is.
B. If you can determine that there are metal studs there now, then I would (once again
were it my home) understand it to be non-combustible and would be fine with
leaving it as it is.
C. If the studs are wood and you can not determine that it was every properly inspected
and that it passed that inspection, (were it my home) I might also opt to rebuild with
metal studs and Durock. I would probably however, opt to try to salvage the stone
and re-install it after I built the wall back with metal stud and Durock. (Because I like
Yes, I am sure that Metal studs and Durock will be up to code.